The depletion of global fossil fuel supplies and its effect on the global climate systems has prompted a drive to find alternative energy sources, in particular renewable energy sources. One promising alternative to fossil fuel is ethanol as it can be produced from renewable sources and has lower emissions than fossil fuel. Currently sources of biomass for the production of ethanol are plant-derived, with major sources including terrestrial food crops such as sugar cane and corn. Non-food crops such as wood and Miscanthus are also used as sources of biomass for the production of ethanol. Another alternative to fossil fuel is biodiesel which also can be produced from renewable energy sources. Currently, the major feedstocks for biodiesel production include palm oil and coconut. However, a major problem with the aforementioned sources of biomass/feedstock is that they compete directly for arable land essential for food production. Thus, as the global population rises, use of such terrestrial sources for biofuel production could lead to food shortages and food price rises. Waste from food crops such as stalks of wheat and corn are also used as biomass for the production of ethanol and, although, this source of biomass does not suffer the problem with competing directly with the food supply, it is insufficient on its own to meet global demand. In recent years, attention has also been directed to the production of biofuels such as ethanol from algae. However difficulties have been encountered in extraction processes and commercial realisation has yet to occur. In addition, large bioreactors are required to make sufficient quantities of algae and, to increase the efficiency, research is currently focused on genetically modified organisms which adds extra constraints on the handling process.
Renewable energy sources need to fulfil requirements which include: (i) capability of being produced in large quantities; (ii) being non-competitive with food supply; and (iii) having minimal environmental impact. There is a strong need for a renewable energy source which addresses the above problems and meets the above requirements.
Tunicates are a group of underwater filter feeders found globally in most marine habitats. Ascidians are the most commonly known class of tunicates. Their most common use is as a model organism in evolutionary developmental biology research. Their embryonic development is simple, rapid and easily manipulated and thus they make good models for studying the fundamental development processes of chordates. Tunicates are the only animals that synthesise cellulose. It is known to extract cellulose from ascidians and to use same in the manufacture of building materials (KR2000-0000303 and JP09-157304). There have been no reports or studies on the development of tunicates for producing biofuels such as alcohols and biodiesel until now.